Paul Salopek and his guide walk into the desert, on day 19 of the "Out of Eden walk" in the Afar region of Northeast Ethiopia. The walk with take about 7 years total.

John Stanmeyer/National Geographic

Along the route is Central Market in Djibouti City, Djibouti. An urban oasis, the central market pulses with traffic. Buses bring migrants who, Salopek says, have changed in a generation from premodern pastoralists to hustling wage-earners in this city of 500,000.

John Stanmeyer/National Geographic

Salopek calms his camel.

John Stanmeyer/National Geographic

Villagers pray for rain in the Afar desert. A megadrought lasting thousands of years may have bottled up early humans in Africa, making travel risky. A climate shift bringing wet periods likely helped propel the first migration.

John Stanmeyer/National Geographic

Salopek in the Afar region of northwestern Ethiopia.

John Stanmeyer/National Geographic

African migrants crowd the night shore of Djibouti city, trying to capture inexpensive cell signals from neighboring Somalia—a tenuous link to relatives abroad. For more than 60,000 years our species has been relying on such intimate social connections to spread across the Earth.

John Stanmeyer/National Geographic

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Paul Salopek has discovered that the best way to take in information, to be a journalist and a storyteller, is not flying around the world with the latest technology. It's by walking.

"There's something about moving across the surface of the earth at 3 miles per hour that feels really good," he tells NPR's Steve Inskeep.

Salopek plans to walk 21,000 miles total — from Africa to the Middle East, across Asia, down through Alaska and all the way to Tierra del Fuego. He calls it the "Out of Eden Walk" because the idea is to follow the path of human migration.

Salopek is currently 10 months into the voyage, and just crossed the border into Jordan from Saudi Arabia. He has faced numerous obstacles, he says, like extreme temperatures and dust devils. As well as manmade obstacles that are vastly different from what early Homo sapiens might have encountered.

"When I began planning this journey almost two years ago," he says, "Syria was at peace."

Now he is re-routing around war-torn Syria and Iraq because, while he is used to reporting in dangerous zones, it's not nearly as feasible without modern transportation.

Salopek travels with camels because he can't carry the water himself. He keeps in touch with his family every day via satellite phone. And in walking great distances, he's learned a few things — both about the world and about himself:

"It really builds confidence in your body," he says. "By and large, after about 10 months of walking, it's about the most natural thing in the world to get up at dawn ... There's a sense of empowerment in being able to do that."